Arctic ice minimum 3rd-lowest since ‘79

The National Snow and Ice Data Center said Sept. 17 that Arctic sea ice appears to have reached its minimum extent for the year, the third-lowest minimum since the start of satellite measurements in 1979.

The center said this year’s minimum is above the record and near-record minimum extents of the last two years, but “further reinforces the strong negative trend in summertime ice extent observed over the past 30 years.”

2009 sea ice extent dropped to 1.97 million square miles on Sept. 12, and the center said that appears to be the lowest point of the year, as sea ice has now begun to grow in response to autumn cooling.

The 2009 minimum is 620,000 square miles below the 1979 to 2000 average minimum and 490,000 square miles below the 1979 to 2008 average minimum.

The center said temperatures this summer were relatively cooler than in the last two years, especially in the Chukchi and Beaufort seas, and winds also tended to disperse the ice pack over a larger region.

Scientists do not consider this year’s higher minimum to be a recovery, as the minimum is 20 percent below the 30-year average minimum and the Arctic is still dominated by younger, thinner ice, which is more vulnerable to seasonal melt.

—Petroleum News